Sensory Receptors & Somatosensation
Receptors that transduce physical deformation of their plasma membrane or cilia into neural signals for senses like touch, pressure, and hearing.
What are mechanoreceptors?
Retinal photoreceptor cells that contain the purple pigment rhodopsin and provide black-and-white vision under low light conditions.
What are rods?
The three middle-ear bones—malleus, incus, and stapes—that transmit and amplify sound vibrations from the tympanic membrane to the oval window.
What are the auditory ossicles?
Lipophilic hormones derived from cholesterol that can cross the plasma membrane to bind intracellular receptors.
What are steroid hormones?
Produced by the supraoptic nucleus of the hypothalamus and released from the posterior pituitary, this hormone promotes renal water retention.
What is antidiuretic hormone (ADH) (or vasopressin)?
These pain-sensing dendrites depolarize when tissues are damaged by extreme heat, cold, intense pressure, or chemical irritants.
What are nociceptors?
The tiny central depression in the retina where visual acuity is highest because light falls directly on cones that have a 1:1 ratio with ganglion cells. Double bonus: what is this within?
What is the fovea centralis? within macula lutea.
These two otolith organs in the inner ear detect linear acceleration, with one responsible for horizontal movement and the other for vertical movement.
What are the utricle and saccule?
Binding of epinephrine to a beta-adrenergic receptor causes a G-protein to activate this membrane enzyme, which converts ATP into cAMP.
What is adenylate cyclase?
The physiological interaction between insulin (which promotes fat storage) and glucagon (which stimulates fat breakdown) on adipose tissue.
What is an antagonistic effect?
Found in muscles, tendons, and joints, these receptors provide the brain with a continuous sense of body position and enable fine motor control.
What are proprioceptors?
The process taking approximately 20 minutes in a dim room during which photopigments regenerate to increase visual sensitivity.
What is dark adaptation?
Rotational acceleration causes endolymph fluid to circulate within the semicircular ducts, bending sensory hair cells embedded in this gelatinous structure.
What is the cupula (in the crista ampullaris)?
The process in which two steroid-bound nuclear receptor complexes join together to bind half-sites on a hormone response element of DNA to stimulate gene transcription.
What is dimerization (forming a homodimer)?
The three sequential stages of Hans Selye's General Adaptation Syndrome (GAS) in response to stress.
What are the alarm reaction, stage of resistance, and stage of exhaustion?
Because olfactory sensory neurons are directly exposed to environmental pollutants and toxins, these stem cells in the olfactory epithelium continually divide and differentiate to replace damaged sensory neurons.
What are basal stem cells?
If light originates from the far right side of a person's visual field, it projects onto this specific region of each eye's retina.
What is the left half-retina?
After spinning in circles and coming to a sudden stop, fluid inertia continues to bend the cupula, producing jerky eye movements and a sensation of spinning known by these two terms.
What are nystagmus and vertigo?
The receptor for insulin is unique because its intracellular domain directly functions as this enzyme, activating itself via autophosphorylation upon ligand binding.
What is tyrosine kinase?
A patient taking long-term high-dose glucocorticoid medication develops fat redistribution resulting in a "moon face" and "buffalo hump".
What is Cushing's syndrome?
A patient receiving morphine experiences reduced pain perception because this internal analgesic chemical system dampens nociceptive signaling in the brain and spinal cord.
What are endogenous opioids?
An eye doctor administers drops that stimulate sympathetic postganglionic axons by contracting these specific iris muscle fibers.
What are the radially arranged muscle fibers of the iris?
When exposed to a dangerously loud sound, this middle ear muscle contracts to dampen the vibration of the stapes against the oval window.
What is the stapedius muscle?
Prolonged exposure to chronically high concentrations of a hormone can cause target cells to decrease their total receptor count, leading to reduced sensitivity.
What is downregulation (or desensitization)?
In primary Addison's disease (autoimmune destruction of the adrenal cortex), loss of cortisol secretion removes negative feedback on the anterior pituitary, causing blood levels of what hormone to rise dramatically.
What is adrenocorticotropic hormone (ACTH)?